Synthesis And Characterize Of Novel Maleimides And Evaluation Of Antimicrobial Activities

Plant pathogenic fungi remain a continuous and huge threat to agriculture and have caused great damage around the world.Among them,Sclerotinia sclerotiorum?Rhizoctonia solani as high-risk plant pathogen have received much attention due to their wide host range,complex origins,latent infection and strong saprophytism,Unfortunately,with the extensive use of the present fungicides,these pathogens exert resistance in some degree,This side effects include not only severe drug resistance but also environmental pollution.Thus,developing novel highly effective and structurally concise antifungal agents with low toxicities is regarded as an effective way to solve this problem.In the previous study,it has been reported that natural products with maleic anhydride structure or maleimide structure are associated with high biological activities.valienamine,valiolamine and other aminocyclitol by biological degradation from the natural compound of validamycin,which also have excellent biological activity.However,there are few species of natural maleimides and some of them only act to single objects,In view of these findings,based on valiolamine,glucosamine and five pesticide intermediates:4-Chlorobenzylamine,3-aminophenol,?R?-?+?-1-?4-Methoxyphenyl?ethylamine,2-Aminoethanol,1-Amino-2-propano with six maleimides,eight new maleimides linked with aminocyclitol were synthesized by methanol solution of sodium methoxide,and characterized by ¹H NMR and MS.Subsequently,another series of twenty one new maleimides were synthesized through the solvent of acetone and toluene,triethylamine as a condensing agent and characterized by ¹H NMR and MS.The invitro antifungal activities against S.sclerotiorum,R.solani were preliminary investigated by the mycelium growth rate method.The results showed that maleimides synthesized by?R?-?+?-1-?4-Methoxyphenyl?ethylamine and 4-Chlorobenzylamine had interesting inhibitory with S.sclerotiorum and Rhizoctonia solani.4 of 31compounds??-1,?-3,?-1,?-6?had stronger inhibitory potency(EC₅₀<10?g/mL)to R.solani.Besides,5 of 31 compounds??-1,?-3,?-1,?-3,?-4?also had strong inhibitory potency(EC₅₀<50?g/mL)to S.sclerotiorum.,It provided a theoretical of a new antimicrobial and encouraged us to make further effort to explore more potent antifungal lead compounds.